反应详情

A mixture of 3,5-dibromobenzonitrile (3 g, 11.5 mmol), thiophene-3-boronic acid (2.35 g, 18 mmol), dichlorobis(triphenylphosphine)palladium(II)(1.21 g, 1.7 mmol), tri-o-tolylphosphine (0.524 g, 1.7 mmol), sodium carbonate (3.46 g, 33 mmol) in aqueous acetonitrile (1:10), 110 mL) was refluxed under nitrogen for 6 hours, cooled to room temperature, concentrated under reduced pressure, suspended in hydrochloric acid (2N, 50 mL), and extracted with diethyl ether (3×80 mL). The combined organic extracts were washed with water (150 mL), saturated aqueous sodium bicarbonate (150 mL), and brine (50 mL), dried over magnesium sulfate, adsorbed onto silica, chromatographed on silica and eluted with a mobile phase of ethyl acetate in hexane. The first fraction was concentrated under reduced pressure to leave 3-bromo-5-(thien-3-yl)benzonitrile in the form of a yellow amorphous solid. Yield 1.47 g (48 percent). mp 62-63° C.; 1H NMR (CDCl3) δ 7.94 (t, J=1.8 Hz, 1H), 7.79 (t, J=1.5 Hz, 1H), 7.69 (t, J=1.8 Hz, 1H), 7.54 (dd, J1=3.0 Hz, J2=1.5 Hz, 1H), 7.46 (dd, J1=5.1 Hz, J2=3.0 Hz, 1H), 7.34(dd, J1=4.8 Hz, J2=1.5 Hz, 1H); EI/MS 265 m/e (M+); IR (KBr) σ cm−1 2230.

1. temperaturewas refluxed under nitrogen for 6 hours
2. concentrationconcentrated under reduced pressure
3. extractionextracted with diethyl ether (3×80 mL)
4. washThe combined organic extracts were washed with water (150 mL), saturated aqueous sodium bicarbonate (150 mL), and brine (50 mL)
5. dry with materialdried over magnesium sulfate
6. customchromatographed on silica
7. washeluted with a mobile phase of ethyl acetate in hexane
8. concentrationThe first fraction was concentrated under reduced pressure